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Re: Annex 48A Draft 2.1 peer review



One quick note below. Tom.

Rich Taborek wrote:

> Tom,
>
> Thanks for your comments, please see my responses below:
>
> Tom Lindsay wrote:
> >
> > Rich - a few comments.
> >

...Stuff deleted...

>
> > 4. This comment is more for the jitter group, but here it is anyway...
> > The core of RPAT repeats a specific block of 12 bytes 16 times. This can hardly be called random. Vixel has also developed a pattern that is based on randomly picking values between 0 & 255 to build up the pattern. Indeed, it has much broader/uniform spectral content than than RPAT. Its only drawback is difficulty in documentation (can't use the word "repeat" 'cause it doesn't...). The pattern we use is for Fibre channel and is 2048 bytes including 6x IDLE, SOF-, Header/payload, CRC, and EOF+. I would be willing to make it available for standardization if interested.
>
> I guess a lot depends on the application of CRPAT for jitter testing.
> It's certainly more random than a packet of all 0's or 1's. I don't
> believe that using the exact Fibre Channel pattern is a significantly
> better replacement since I have to ask the question: Better for what?
>

Sorry, I didn't mean to suggest the full FC frame - I thought maybe the payload section might be useful, although it would have to truncated to 1518 bytes.

Tom

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